Tea Party-backed Senate candidate Ted Cruz points with pride to the army of small conservative donors supporting him. But his largest longtime contributor is a gay billionaire who supports same-sex marriage and marijuana legalization, campaign finance filings show.

Peter Thiel, a German-born hedge fund manager and founder of the online payment system PayPal, gave Cruz $251,000 in 2009 for his aborted run for attorney general. The money represented 19 percent of the total raised for that campaign, which Cruz ended after Attorney General Greg Abbott decided to run for re-election.

Thiel, an early Facebook investor who was portrayed by actor Wallace Langham in the movieThe Social Network, has kept up the support since Cruz launched his U.S. Senate bid. He has given Cruz $5,000 combined for the Senate primary and for Cruz's July 31 runoff against Lt. Gov. David Dewhurst, the maximum amount allowed. And Thiel was the largest single donor to the most generous outside group backing Cruz — the Club for Growth Action super PAC — in the most recent federal disclosure period, according to the Center for Responsive Politics.

Thiel gave the super PAC $1 million in May, filings show. Club for Growth has set a $5 million fundraising goal ahead of the Texas runoff. The Club for Growth declined to say if Thiel had earmarked the contributions to benefit Cruz, but called the donor a “great American” and a “defender of liberty.”

Attempts to reach Thiel through the website of one of his companies, Founders Fund, were not successful.

Cruz spokesman John Drogin said Cruz considers Thiel a friend even though they do not talk frequently or agree on every issue. In 2009, Cruz attended an invitation-only conference in Greensboro, Georgia with Thiel that brought together “conservative, Republican and libertarian leaders, thinkers and media to discuss advancing conservative and libertarian principles,” according to Cruz's campaign. Thiel picked up the $1,220.80 in lodging costs for Cruz during the conference. The billionaire paid for the other participants’ lodging, too, the Cruz campaign said.

“Ted enjoys support from thousands of Texans and Americans who understand that politicians from both parties have failed us, and while Ted may not agree with every policy position of every supporter, Ted is grateful to the thousands of supporters who understand that above all, we must reduce the size of government and defend the Constitution,” Drogin said.

But Thiel's political and financial support for gay rights and legal marijuana, among other causes, have made him a lightning rod in the U.S. Senate race. Thiel has given money to gay Republican groups including GOProud and the American Foundation for Equal Rights. He enthusiastically backed Republican Ron Paul in the presidential race, providing most of the money for the candidate's super PAC, Endorse Liberty.

Before the May 29 primary, when there were nine GOP candidates in the Senate race, former Dallas Mayor Tom Lepperthighlighted the Thiel donations during a joint appearance on WFAA-TV in Dallas. “They received a quarter-of-a-million dollars from the gay activist who was leading the fight for gay marriage in California,” Leppert said.

Cruz did not directly respond to the criticism at the time, though he and other Republican candidates had previously attacked Leppert for appearing at a gay pride parade when he was mayor of Dallas.

On Sunday, Drogin reasserted that "Ted's record of defending marriage between one man and one woman is as clear and unwavering as his commitment to reduce the size of government and defend the Constitution come hell or high water."

Now that Cruz is locked in a bitter summer runoff, the Thiel donations are again generating some political heat.

Dewhurst spokesman Mark Miner said the donations from Thiel show Cruz is "deceiving" Texans about his political alliances.

"It's hypocritical and deceitful for Ted Cruz to claim to be a Tea Party Republican when his largest donor spends millions of dollars pushing the opposite side of conservative issues important to Republicans," Miner said.

Thiel has supported numerous other Republican candidates and committees, including Sen. Orrin Hatch of Utah, Sen. Rand Paul of Kentucky and U.S. House Majority Leader Eric Cantor of Virginia.

Thiel describes himself as a libertarian and has supported a variety of unorthodox causes, from the development of floating human sea colonies to life-extending technologies. Thiel also set up a foundation to give $100,000 scholarships to young entrepreneurs who drop out of college to pursue creative business ideas.

Thiel is listed as a member of the steering committee of the Bilderberg group, which stages a yearly gathering that brings together influential world leaders in politics, business and other fields to discuss international affairs. The secret meetings have prompted protests by activists who allege they are being staged to create a new world order and capitalist domination.

Glenn Addison, who was in the GOP Senate primary but didn't make the runoff, said the Bilderberg connection worries him.

"Birds of a feather flock together," Addison said. "I think voters need to be concerned and ask about whatever alliances people have that are running for office."